To Grohl: (v) to be unbelievably amazing at any combination of talents or abilities at once(Such as Dave Grohl of the Foo Fighters). Side affects may and often include continuous guttural screams and excessive headbanging.

-"Dude were you at that concert last night"
-"Yea dude the lead singer was totally Grohling, it was sick."

1. This definition is a contradiction of the word. It corresponds with Dave Grohl from Foo Fighters or Nirvana, who seems to work his ass off at everything. He can play drums, guitar, bass; he is very well rounded as a musician. So, to be "grohl" is to contradict that, meaning that you are a slacker and don't give a shit.